This invention relates to an image reading/recording apparatus for reading and recording an image.
In a system where a two-dimensional image is reproduced by dividing said image into a plurality of one-dimensional picture elements, as typically represented by a facsimile system, the scanning system thereof commonly used in the early stages was of a cylindrical scanning type, as shown in FIG. 1.
On the transmit side, a subject copy 2 wrapped around a cylinder 1 is scanned by a reading head 5 having a lamp 3 and a phototube 4. Scanning operations consist of main scanning involving the rotation of the cylinder 1, and auxiliary scanning involving the movement of the reading head 5 in the direction parallel to the rotating axis 6 of the cylinder 1.
On the receive side, on the other hand, a recording paper sheet 8 wrapped around a cylinder 7 is scanned by a recording head 10 having a recording stylus 9 and other components. Scanning on the receive side is performed by main scanning involving the rotation of the cylinder 7 and auxiliary scanning involving the movement of the reading head 10 in the direction parallel to the rotating axis of the cylinder 7, as performed on the transmit side.
FIG. 2 is a diagram of assistance in explaining the relationship between the main and auxiliary scanning operations, showing the subject copy 2 wrapped around the cylinder 1, or the recording paper sheet 8 wrapped around the cylinder 7 where symbols A, B, C and D refer to the four corners of the subject copy 2 or the recording paper sheet 8. The main scanning is performed in the A-B direction as the cylinder 1 or 7 rotates, while the auxiliary scanning is performed as the reading head 5 or the recording head 10 moves along the A-C direction.
In recent years, however, a planar scanning system as shown in FIG. 3 has been developed to substitute for the cylindrical scanning system. In FIG. 3, a reading portion 12 on the transmit side is a linear array of multiple sensors R1, R2 . . . Rn, each sensing variations in the intensity of light of a spot on a subject copy 13. Each of these sensors R1, R2 . . . Rn is connected to each of the contacts S1, S2 . . . Sn of a selector switch 14 in that order. When the contacts of the selector switch 14 are switched over in the sequence of S1, S2 . . . Sn, the output of the sensor R1 first appears on an output signal wire 15, followed by the outputs of the 20 sensors R1, R2 . . . Rn in that sequence. In this way, the main scanning in the A-B direction is performed, while the auxiliary scanning in the A-C direction is performed as a paper feeding roller 16 is rotated.
On the receive side, on the other hand, a recording portion 17 is a linear array of recording elements W1, W2 . . . Wn. Each of these recording elements are connected to each of the contacts S1', S2' . . . Sn' of a selector switch 18 in that order. As in the case of the transmit side, when the contacts of the selector switch on the receive side are switched over in the sequence of S1', S2' . . . Sn', the recording elements are also switched over in the sequence of W1, W2 . . . Wn for recording on a recording paper sheet 19. In this way, the main scanning in the A-B direction is effected on the receive side, while the auxiliary scanning in the A-C direction is effected as a paper feeding roller 20 is rotated.
In practical units, the selector switches 14 and 18 are not mechanical-contact switches, but are composed of shift registers or other appropriate means and semiconductor switches, each being usually formed on the same substrate with the reading portion 12 or the recording portion 17.
FIG. 4 shows an example of the construction of the recording portion and the selector switch portion, both formed on a single substrate 21. A recorder 22 is a thermal head consisting of a linear array of multiple heating elements H1, H2, H3 . . . Hn. These heating elements are divided into two groups, each being connected to a drive portions 23a and 23b, respectively. Each of the drive portions 23a and 23b incorporates a shift register, a semiconductor switch and a thermal head drive circuit, and serves as a selector switch connected to a data input terminal 24 to select one of the multiple heating elements. As a signal is entered on a reset input terminal 25, the heating element H1 at the extreme left in the figure, for example, is selected, and then the adjacent heat elements are selected one by one every time a clock pulse input appears on a clock input terminal 26. The reading portion and the selector switch portion, both formed on a single substrate, have the same construction.
In conventional facsimile equipment of the planer scanning type, designed for performing both transmission and receiving, the transmitting and receiving portions thereof have separate paper feeding rollers, and the reading and recording portions thereof are provided on separate substrates. This makes it impossible to make the equipment compact in size since the same scanning means cannot be used for both transmission and receiving purposes.